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UNITED STATES PATENT OFFICE.

HENRY WV. JOHNS, OF NEWV YORK, N. Y.

PROCESS OF MANUFACTURING ASBESTUS SHEETS. V

SPECIFICATION forming part of Letters Patent No. 408,838, dated August13, 1889.

Application filed November 16, 1886. Serial No. 219,071. (No specimens.)

To all whom it may concern.-

Be it known that I, HENRY W. JOHNS, a citizen of the United States,,anda resident of New York, in the county of New York and State of New York,have invented certain new and useful Improvements in Processes ofManufacturing Asbestus Sheets, of which th following is a specification.

My invention relates to a new process for the manufacture of asbestussheathing, so called, or, in other words, sheets of asbestus or ofasbestus and other fibrous material com bined having a flocked ornap-like surface. Such sheets are used for roofing and for boiler andpipe covering and other like purposes.

Sheets of pure asbestus and of asbestus combined with other fibrousmaterials having a fibrous, fiocky, or nap-like surface have beenheretofore made, the same having been patented to me by the UnitedStates Letters Patent dated August 10, 1880, No. 230,945; but in thesaid prior invention the napped sheets are made by the employment ofadhesive substances applied to the surface or surfaces ofpreviously-completed sheets, by means of which the asbestus, pure orcombined with other materials which form the nap or fibrous surface, isattached thereto, being held by the cementing properties of the adhesivematerials.

By my present invention I produce sheets possessing all" the valuablequalities of my said prior products and which are more inexpensively andquickly produced, since I do away with one step in their manufacturenamely, the application of the adhesive material to the completed sheet.They are also lighter in weight and more pliable, thus rendering themmore desirable for certain uses than those heretofore patented to me.

In practicing 'my invention I proceed as follows: I first fibrate orfinely divide the as bestus and other material, if other material beused, and remove from them all impurities, and then pulp them in anypreferred manner, such as is now practiced in papermaking. I prefer toemploy an apparatus for making my improved product and practicing myprocess the same as that now employed for paper-making, composed ofpulping-vats, a traveling apron, compression-rolh ers,heating-cylinders, the. Such apparatus is now well known and does notrequire specific description here. After the pulp has been formed I makeit into sheets upon the machine by drawing it from the pulping-vats inany manner now practiced in paper-making and depositing it upon theapron of the machine in a thin even layer, which is to becompressed-into the desired sheet. Then I sprinkle by sifting or in anyother desired manner upon the surface of the pulp before it has beenfinally compressed by the pressure-rollers an even layer of fibrousasbestus or of asbestus fibers mixed with other fibrous or fiockymaterial, which, supported on the partly-compressed pulp, is carried bythe apron which supports it in between the pressure-rollers, and is bythem forced down upon and partly embedded in the surface of the softpulp, so that when the sheet has been subjected to the final pressuresand is dried it will be found that the upper side of the sheet has uponit a long nap of fibrous particles held to the surface of the sheet bythe partial embedment of the fibers in the surface thereof. After thesheet is thus made I dry it in any preferred manner and by any suitableapparatus;- or it may beallowed to dry in the atmosphere.

The base-sheets may be of pure asbestus, or of asbestus mixed with othermaterials, or entirely of other fibrous material, and the nap may beproduced on one side only or on both sides; but when it is desired tohave the nap on both sidesthereof one layer of the fibers which are tocompose the nap should be applied to the apron of the machine before thepulp is applied thereon and the other layer of fibers put on top of thepulp, or else the machine must be so constructed that the sheet can beturned over before it is completely compressed, and the second layer offibers applied to the reverse side of the sheet.

I do not limit myself herein to any specific mechanical appliances forproducing my products or practicing my process.

Having described my invention, I claim The process of manufacturingasbestus sheathing, or sheets containing asbestus and Signed at NewYork, in the county of New having a mapped surface, consisting in pulp-York and State of New York, this 15th day 10 ing the material andforming the same into a of November, A. D. 1886.

layer or sheet, and then applying fibrous 5 asbestus t0 the surface ofthe sheet while it is HENRY \V. JO] INS.

soft, and then pressing the superposed fibers \Vitnesses: into the pulpof the sheet, and then drying GEORGE 'W. (niLADWlN,

the sheet, substantially as set forth. CHARLES H. PATRICK.

